Abstract: 【Aim】 The quality and type of a prey play key roles in selection, consumption and trophic transfer efficiencies by its predators. The nutritional quality of a plant can affect that of the herbivore, which in turn can affect the herbivore’s nutritional quality as the prey for predators. In order to further understand the tritrophic interaction among host plants, preys and predators, the effects of the prey’s host plant species on the predator were investigated. 【Methods】 The effects of the prey’s host plant species on the predator were assessed by studying the consumption and utilization of the cotton aphid, Aphis gossypii Glover (Hemiptera: Aphididae), reared on five species of Cucurbitaceae by the 4th instar larvae and female adults of Hippodamia variegata (Goeze) (Coleoptera: Coccinellidae). 【Results】 The food consumption was the highest for the 4th instar larvae and the female adults of H. variegata when they were fed on the cotton aphids reared on Cucurbita moschata var. melonaeformis. The food consumption was the lowest for the 4th instar larvae and female adults of H. variegata when they were fed on the cotton aphids reared on Lagenaria siceraria var. gourda. The relative growth rate (RGR), efficiency of conversion of ingested food (ECI) and efficiency of conversion of digested food (ECD) were the highest for the 4th instar larvae of H. variegata when they were fed on the cotton aphids from Cucumis melo var. cantalupensis. The RGR did not differ significantly in female adults of H. variegata when they were fed on the cotton aphids reared on C. sativus and C. pepo var. medullosa, while the ECI and ECD did not differ significantly when they were fed on the cotton aphids reared on C. sativus, L. siceratia var. gourda and C. pepo var. medullosa. Therefore, the cotton aphids reared on C. melo var. cantalupensis are more suitable preys for the 4th instar larvae of H. variegata, whereas those reared on C. sativus, L. siceratia var. gourda and C.pepo var. medullosa are more suitable preys for the female adults. 【Conclusion】 The predation efficiency of H. variegata on the cotton aphids is related to the host plant species. This result makes a theoretical foundation for further using the feeding habits of an insect to control insect pests.

Key words: Hippodamia variegata, Aphis gossypii, host plant, tri-trophic interaction, food consumption and utilization